Fully Open Foundation Model for Sovereign AI

Developed by the Swiss AI Initiative as a collaborative effort between EPFL, ETH Zurich, and CSCS. Open weights, open data, open science.

Fully Open

Training data, code, weights, methods, and alignment principles — all documented and reproducible. Apertus is to AI as Open is to Source.

Compliant at Scale

Built to meet EU AI Act requirements: the model respects opt-outs, removes PII, prevents memorization. A global foundation to build on.

Run for Performance

Competitive with top open models at an equivalent scale of 8B and 70B parameters. Multilingual from day one — trained on 1000+ languages.

Swisscom is a Strategic Partner of the Swiss AI Initiative.